Stopper II® clear polycarbonate cover with a warning horn & English labelling for surface mounted manual pull stations

The ultimate sound deterrent for protruding manual stations.

This Stopper II model is specifically designed for manual fire alarm pull stations that are surface-mounted (installed on the exterior of the wall rather than recessed). It includes a specialized conduit spacer (back box) to accommodate the depth of the station. It provides a dual defense: a physical shield against impact and a high-decibel local siren to deter malicious false alarms.

This cover is UL listed hence the equipment and its installation meets Canadian standards. It is also FM approved; the Factory Mutual Approvals is a group offering testing and certification services on products for commercial and industrial use. This piece of equipment is ideal for fire safety in public locations such as schools, hospitals, mills, etc.

STI™ product code: STI-1130

Stopper II® covers protect manual pull stations from impacts and help prevent false fire alarms without restricting legitimate alarms. The cover can easily be lifted and is connected to the frame by a metal cable. It was designed for indoors use only. Such an accessory requires a double action to trigger a fire alarm compared to a simple pull station which requires one sole move.

All labeling on the cover and instructions provided in the package are in English (PDF version available for download).

External dimensions:
Length 7.125 in x Height 10 in x Depth 5.5 in
(Length 18.1 cm x Height 25.4 cm x Depth 14 cm) 

Inner dimensions:
Length 5.5 in x Height 6 in x Depth 5.5 in
(Length 14 cm x Height 15.24 cm x Depth 14 cm) 

Polycarbonate thickness: 0.095 in (2.4 mm)

This cover fits most pull station models, mainly surface mounted ones.

Covers with French labeling are also available as prescribed by the Province of Quebec regulations (see item ECSTI1130FRE).

Polycarbonate properties:

Polycarbonate is a clear low flammability material highly resistant to impacts which features impressive mechanical and thermal properties, hence its use in so many fields. It is commonly used to manufacture safety eyewear, protective faceshield, law enforcement shield, optical lenses, thermal imaging and so many other vandal-proof items. The polycarbonate used for the fabrication of Stopper II® covers is UV-stabilized against degradation caused by the sun.

Key Benefits: Superior Protection for Exposed Stations

This model is the industry standard for industrial facilities, warehouses, and retrofitted buildings:

• Surface Mounting Spacer Included: Features a deep mounting frame that fits perfectly over standard surface-mount electrical boxes without obstructing the alarm lever.

• Active Deterrence: A powerful local siren (95–105 dB) triggers the moment the cover is lifted. This alert often scares away pranksters or vandals before they actually pull the building's fire alarm.

• "Police Shield" Toughness: Molded from heavy-duty clear polycarbonate, it is virtually indestructible and protects against equipment collisions, sports balls, and physical tampering.

• Clear English Instructions: Features bright red silk-screened text: "In Case of Fire, Lift Cover and Pull Station."

• Anti-Yellowing Technology: The UV-stabilized polycarbonate remains crystal clear over time, ensuring the red fire station is always highly visible to occupants.

Technical Specifications

• Mounting Type: Surface Mount (for protruding stations).

• Material: High-impact, UV-stabilized clear polycarbonate.

• Local Alarm: Independent piezoelectric horn.

• Power Source: 9V DC Alkaline battery included (powers the cover siren only).

• Dimensions: Extra depth provided by the included spacer box.

• Certifications: UL/cUL Listed.

Application Guide: Recommended Installation Zones

Essential for areas where alarm stations are exposed and vulnerable to abuse or accidents:

1. Warehouses & Industrial Sites: Protects against forklifts and moving machinery.

2. Schools & Universities: Highly effective at reducing "prank" fire alarms in hallways.

3. Gymnasiums & Arenas: Shields the station from high-speed ball impacts.

4. Parking Garages: Durable enough to withstand harsh environments and isolated areas.

FAQ: Frequently Asked Questions

Does this cover make the fire alarm harder to use in a real emergency?

No. The design is intuitive and allows for rapid access. While it adds a single step (lifting the cover), this is widely accepted by fire marshals because it drastically reduces the danger and cost associated with false alarms.

Does the local alarm call the fire department?

No. The Stopper II siren is local only. Its purpose is to alert people nearby that the cover has been opened. The official building alarm only triggers if the lever inside is pulled.

Occupational Health and Safety (OHS) Expert Advice

• Battery Maintenance: The 9V battery should be tested during your monthly fire safety walk-through. A dead battery means no siren, which removes the psychological deterrent for vandals.

• Clearance Check: When installing, ensure there is enough vertical clearance above the station so the cover can swing fully open to the 90-degree position.

• Cleaning: Use only water and mild soap. Abrasive chemicals or window cleaners can damage the polycarbonate, making it cloudy and difficult to see through.

Maintenance and life service:

Some basic practices should be adopted to maintain manual pull station covers. It is thus recommended to wash the cover with lukewarm water and a gentle soap; be aware that if one lifts the cover while cleaning, the alarm will go on until the cover is snapped back into place. The manufacturer strongly advises not to use steel pads since they scratch any surface they touch which will temper with the legibility of the label. It also is not recommended to use harsh soaps on the cover since polycarbonate doesn’t mix well at all with a wide array of acids and other chemical compounds. Indeed, these products will make your cover kind of melt. If the cover surface isn’t soft to the touch and bubbles appear, the cover has been corrupted and must be replaced.

As for its life service, the manufacturer asserts that his Stopper II® covers are durable; some have been in service for almost 20 years. Of course, the warning horn and battery should be inspected every 6 months to make sure they function, and the 9-Volt battery should be replaced yearly if need be.

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